The movement
of the pollen grain is caused by water particles bombarding the grains.
This results in the random movement of the pollen grain. This random
movement of the water particles and the pollen grain is referred to
as "Brownian Motion".
The diagram below is
an example of random motion (Brownian Motion) of a single water particle.
Robert Brown would not
have seen water particles because they are too small to see under a microscope.
The
Brownian
Motion Activity
What
is causing the movement of the pollen grains?